Start-stop repeater system



Nov. 18, 1941. POT-rs START-STOP VREPEATER SYSTEM cs-Sheet l I Q 2 Shee Filed Nov. 30, 1934 INVENTOR LOU/5 M. 007725 ATTOR Y Patented Nov. 18, 1941 START-STOP REPEATER SYSTEM Louis M. Potts, Evanston, Ill., assignor to Teletype Corporation, Chicago, Ill., a'corporationof Delaware Application November 30, 1934, Serial No. 755,253

8 Claims.

This invention pertains to telegraph systems and apparatus, and more particularly to telegraph repeating systems and apparatus.

In telegraph systems using comparatively long signal intervals, relay repeaters which renew the current value of each impulse but which may modify the length of the impulses slightly have been found satisfactory for some telegraphic purposes, but in systems where transmission is effected at high speeds, it becomes necessary to preserve the relative lengths of signal impulses as well as to renew the current strength thereof. Accordingly, regenerative repeaters have been designed for start-stop telegraph systems in which received signal impulses are reproduced and retransmitted in renewed strength and in faithful reproduction of their relative time Values, thereby producing signal impulses and signal conditions equivalent to the originally transmitted signals. Transmission systems in which such repeating devices are connected usually effect transmission in both directions over a single line wire, and in such systems it is desirable that any repeating devices connected between two sections of a line repeat from either line section into the other in response to an initiation of transmission of signals in either line section.

An object of the present invention is to provide an impulse repeating device capable of operating at high speeds to transmit signals under the control of either line section into the other line section equivalent in strength and Wave shape to the originally transmitted signals.

Another object of the invention is the provision of a mechanical repeater for start-stop telegraph systems to repeat each signal impulse from one line section to another, in which mechanical arrangements are provided for preventing reflection of impulses received from one line section for retransmission to an adjacent line section.

A still further object of the invention is the provision of a mechanical repeating device for start-stop telegraph systems wherein its driving motor is controlled automatically from either line section. v

A specific object of the invention is the provision of a device capable of repeating impulses from one line section to another and recording characters indicative of the repeated impulses in different colors distinctive of the direction of transmission.

The above and other objects of the present invention are attained by the provision of motor driven mechanically operated but signal controlled repeating. device forrepeating all signals including start and stop signals and character signals from one line section to another, with elements either electrically or mechanically controlled for establishing reflection estoppel conditions at the beginning of the transmission of code combinations of impulses which continue until the end of such code combination of signal impulses.

Specifically, the apparatus of the invention comprises electrical relays andcircuits controlled by electrical switches which are controlled by start-stop cams provided upon the start-stop mechanism of the regenerative repeating'devices, also motor-control devices operable by either of two regenerative repeating devices to control a motor which supplies mechanical power for both of the regenerative repeaters, and also ribbon shifting or record modifying means controlled by start-stop cams and by circuits of the regenerative repeaters to indicate the direction of transmission of the intelligence impulses.

The circuits of the present invention in which directional control is exercised comprise two regenerative repeater mechanisms so associated with retransmitting contacts that the initial operation of either device sets up an estoppel condition which prevents reflection signals. The circuits of the present invention in which a single regenerative repeater mechanism is used comprise a signal-receiving line relay for each line section and a repeating-mechanism-seizing relay for each line section, the line relay which initiates transmission operating to energize first the seizing relay which then operates to seize the repeating mechanism in an alternative manner which determines its direction of repeating with reference the two line sections. A locking circuit thereafter maintains this condition during the then ensuing code cycle. In a modification wherein mechanical control is exercised, a mechanical locking member performs the function of the electrical locking circuit just described.

A better understanding of the invention may be had from the following description, taken in connection with the accompanying drawings, wherein:

Fig. 1 shows a circuit system comprising two line sections connected together through two regenerative repeating devices having polarized line magnets, the system operating'upon two-current principles using polar signal impulses, transmission from afirst terminal station to a second being recorded uponone printer and transmission in reverse direction from the second termigenerative repeating device which operates a1-' ternatively to repeat signals from one line section 5 and into the other, the system operating upon single-current principles, and 'alsohaving cam controlled locking relays whereby interruption of transmission at a mean signal impulse of a code combination of signal impulses is prevented;

Fig. 4 shows a circuit system similar to that shown in Fig. 3 but adapted to interconnect a lin section having two-current working with a line section having single-current working;

* Fig; 5 shows an alternative form of circuit system comprising two line sections connected through one regenerative repeating device arranged with means operable in response to each transmitted character for shifting a two-color ribbon in the receiving printer, the ribbon mechanism being shiftable in one direction to indicate one color to indicate transmission in one direction and the other color indicating transmission in the opposite direction; I

Fig. 6 shows a circuit system of two line sections and a mechanical system of interlocking members connecting two regenerative repeater mechanisms which connect the line sections together in a single telegraph transmission line, any reflection signals being mechanically prevented, and

Fig. 7 shows a motor control system wherein either of two connected regenerative repeaters may control one motor which drives the two regenerative repeaters.

fAs disclosed in Fig,v 1, avsystem according to this 'inventionembodies two terminal stations. A and'B'having their individual lines 2 and 3 respectively, terminated at a repeating'stati'on 0. Each of the terminal stations is provided with 'a receiving printer 4 of polar-control construction and .aftransrriitter 5, both receiving printer 4 and transmitter 5 being suitable for transmission under two-current principles, the receiving. printer having 'a two-position armature 6 which takes one or the other of its two positions according to;the polarity of the instant controlling current; and the transmitter 5 is provided with: a battery of positive or m arking polarity connected through resistor I to a contact in transmitter 5 and with a battery of negative or spacing polarity connected through resistor 8 to a contact in transmitter 5. The details described are shown diagrammatically at terminal station A, while terminal station B is similarly equipped. There is also arranged at each of the terminal stations an interrupter key 9 connected in the circuits of the terminal station insuch manner that when in itsoperated position it will disconnect the receiver printer 4 and the transmitter 5- from the line 2 and will connect the line 2 to negative or spacing battery through resistor 8; also a motor lljsupplied with electrical energy over a circuit (not shown) serving to supply motive power to the receiving printer 4 and transmitter 5 as is well known. The circuit of the drivin'g'motor' I I may be controlled automatically by telegraphic signals in the line 2 as is well known.

As previously indicated, each of the lines 2 and 3 extends from the respective terminal stations to the repeating station C, and included in each of the lines is a line magnet I2 and I3 for effecting the energization of line magnets I2 and I3 extends in the case of terminal station A from ground at repeating station C through re- .sistor. I4, winding of magnet I2, contacts I5, line 2, spring and lower contact of interrupting key 9, winding ofreceiving printer magnet 4, transmitter 5, and resistor I to positive or marking battery. A circuit for line magnet I3 may be traced similarly. through resistor I6, contact I1,

and line 3 to terminal station B and to positive ormarking battery.

- Polar magnet I2 andits armature 2 I comprises a selector magnet of astart-stop regenerative repeater 20 of the form and'construction shown in .copending application Serial No, 711,479; filed February 16, 1934.

According to the disclosure of the aforemen-' tioned copending application, the regenerative repeater is similar in construction to the printing telegraph device described in Patent No. 1,821,110 issued to S. Morton et a1. September 1, 1931 and embodying a cam drum 22 arranged with the stop arm 23 normally'in engagement with a fixed stop 24. The camdrum 22 has six pairs of earns 25 which control six selecting levers 26 in accordance with six received intelligence impulses to operate the selector levers in sequence to register each intelligence signal impulse of a code as the impulses are received, after which a transfer action occurs to transfer the six registrations simultaneously to the selector mechanisr'nl and to the printing mechanism of the receiving printer. Also carried by drum 22 are two multiple cam rings 30 and 3|, which are shaped to represent all of the cams 25, and in longitudinal alignment therewith and two additional cam's representing start and stop-signals of a start-stop code. Arranged in coaxial alignment with the six selector levers 26 'is a repeater selector lever 32 moved into marking and spacing positions in a manner similar to the operation of selector 1evers26 but operating for every impulse of the entire signal including thestart and stopimpulses. With every movement of lever32,'a striker 33 is operated to change the contactive relation of contact members 34, 35, and 36 for the purpose of transmitting impulses in a controlled line section corresponding in strength and wave shape to the impulses received for controlling the operation of cam drum 22. Normally cam drum 22 is in its marking position with'selector magnet I2 energized, in which case the stop arm 23 is in engagement with the fixed stop 24. Upon receipt of a spacing signal indicative of a start condition generated by transmitter 5 at terminal station A, selector magnet I2 will be energized to move its armature 2|, which will permit cam drum 22 to free stop arm 23 from fixed stop 24, and since driving motor 31 is now supplying power to the regenerative repeater, having been started automatically in any well-known manner in response to the change of signal in magnet I2, cam drum 22 is likewiserotated. Selecting magnet I2 and its armature 2'I 'willrespon'd to'the operation" or transmitter at terminal stationA and cause the cam drum 22 to be moved correspondingly and thus bring the cam rings 39 and 3| intc generate in theline conductor 3 connected thereto impulses corresponding to the impulses which efiected the energization of selecting magnet I2. Assume that terminal station A desires to transmit a message to-terminal station B, interrupter key 9 will be momentarily operated into its reverse position, resulting in the reversal of polarity of the current in line 2 and in the reversal of polarity of the energized polar selector magnet l2 at the repeating station C. Motors'l l and 31 are started automatically by means not shown, and motive power thus is applied to transmitter 5 and receiving printer 20. Also as a result of the momentary operation of interrupter key 9, line magnet l2 reverses the position of its armature 2|, thus releasing 'cam drum 22 which by a slight axial movement frees stop arm 23 from its fixed stop 24. Immediately thereafter a cam of multiple cam ring 3| engages repeater selector lever 32, which responds and moves striker 33, thus changing the contactive relations of the contact members 34, 35, and 36, opening repeating contacts I! and closing repeating contacts 38 and thereby changing the signal current in line 3. The circuit for current in line 3 now extends from positive battery 39 of double potential value through resistor 4|, closed contacts 38, line 3, interrupter key, receiving printer magnet, and resistor of terminal station B and through positive battery of single potential value to ground. Normally line 3 carries a current in marking direction which causes the printer magnet to hold its armature in non-operating position, but in the circuit just traced, the double potential of marking battery 39 at the repeating station C overpowers thesingle potential of marking battery at terminal station B, thus reversing the direction of polarity of current in line 3 and through the printer magnet of station B. The printer magnet of terminal station B reverses its armature and starts its motor. Upon restoration of interrupting key 9 at terminal station A, the normal marking current is restored to the line 2, the magnet l2 reverses its polarity and restores its armature at-the repeating station C, which causes selector lever 32 to return to its normal position, restoring the repeating contact members 34, 35; and 36 to their normal positions, closing repeating contacts I1, and opening repeater contacts 38; thus restoring the normal condition of circuit and current to line 3, restoring the marking polarity to the receiving printer magnet at the terminal station B, which returns its armature to its normal posi-' tion. All motors having been started by this operation of the interrupting key. 9 at terminal station A, the operator at station A may send a message. Movement of transmitter 5 connects its tongue to spacing contact and connects negative battery through resistor 8 and transmitter 5, receiver magnet 4, key 9, line 2, contacts l5, magnet l2 of repeater and resistor 14 to ground, thus reversing to spacing position the armatures 6 and 2| of magnet 4 and of repeater magnet l2 respectively. The reversal of armature 2| re verses the contactive relation of contact members 34, 35, and 36, thereby connecting positive battery 39 through repeater contacts 38 to line 3,"through printer magnet and transmitter to positive battery and ground whereby the double potential of battery 39 overcomes the potential of the terminal station battery and reverses the position of the armature of printer at station'B into spacingposition, thereby repeating at terminal station B the signal originated in terminal station A. Meanwhile, movement of contact 35 away from contact 34 has opened the circuit of the magnet l3 of the-repeater of line 3 which,

having a polarized armature with a permanent field, is held byv its permanent field in its marking condition and which, therefore, does not repeat the spacing condition into the line section 2-. When transmitter 5 restores its tongue to its marking contact at the termination of the spac ing signal, positive battery at terminal station A restores the direction of current in line section 2, restores armature 2! to its marking condition, and restores repeater 25 to its marking condition,

which restores contact members 34, 35', and 36' to the contactive..(relation illustrated, thus removing line wire 3. from source 39 and restoring it to ground connection through the magnet 13, thereby supplying marking current again to the magnet l3 without operating its armature since it has remained in marking position, and also restoring current from positive battery at terminal station B to central ofiice ground through the magnet of the printer at terminal station B, thereby restoring the armature of that printer to marking condition, thus repeating in the printer at terminal station B the restored marking signal originated in transmitter 5 at terminal station A. Interruption of transmission maybe effected by shifting the tongue of the interrupting key. at terminal station B to its spacing contact for a short period of time, thus connecting negative battery to line 3 whereupon either forthwith or at the end of the instant signal if spacing, the negative battery at terminal station B will become efiective and will reverse the signalling condition of the repeater magnet I3 and of its repeating contact members, and thus will connect double marking potential 39 through line 2 to terminal station A, after which the printer 4 at substation A will be unresponsive to the transmitter 5 since current from battery 39 will flow in spacing direction through the magnet of'printer 4 in either position of the tongueof transmitter 5 and to either of the terminal stae tion batteries, by which non-response of printer 4, the operator at terminal station A will note that terminal station B is interrupting and desires to transmit.

During all-interchange of transmission between the two terminal stations A and B, all transmission originated at station A will operate magnet l2 of printer 20 and will be recorded upon printer 20, while all transmission originated at station B will operate magnet l3 and will be recorded upon the printer of magnet 13. Thus at the repeating station C the direction of .transmission whether from terminal station A or from terminal station B will be indicated and identified by the identity of the printer at station C upon which the transmission will have been recorded.

In Fig. 2 is disclosed a system according to this invention embodying two terminal stations D and E having their individual lines 42 and 43 respectively; terminated at a, repeating station Each of the terminal stations is providedwith azqlteceiving printer .44 of neutral control con,- struction and a transmitter 45; ibothreceiving printer 4,4 and transmitter 45, being suitablefor transmission under, single-current principles {Terminal station E is similarly equipped: 'Ifhere .is :als o arranged at each of the terminal stations DandE an interrupter key 46;connecte'd in series with the lin circuit, toyopen the line ,circuit, also amotor 41 which may be controlledautomatically by line signals through meansinot shown. 'As'in the case ofvthe system of Fig; '1, each :of the lines 42 and 43 extends from therespective terminal stationsto the repeating sta- .tion F and included in each of the lines 'is' a line magnet 48 and 49 respectively, which are normally energized from-1batteries adjacent there- .unto. .Thecircuityfor effecting the energization of; the line magnet 48 extends from battery through magnet 48, contacts 5| andline'42, interrupting key 46, printer magnet 44, and closed contacts of transmitter .45 to ground at terminal station D. A similar circuit .maybe 1 traced through line magnet .49, contacts 52, and line 43 to ground at terminal stationv I Similarly to the, printer 20 in Fig. 1, line magnet 48- and its armature 53'comprise a selector magnet of a start-stop regenerative; repeater 54 which operates as a printer and also operates its repeating contact members 55 and its repeat ing'contacts 52 and 56in the mannerwhichhas been described above in connection with theide scription of 'Fig. 1.

'-"Assume that terminal station. D desires to transmit a message to terminal stationE, inter rupter key 46 will be momentarily operated, which opens its contacts thus opening the circuit of line' 42, resulting inthe deenergization of magnet 48 and the release of its armature53at the repeating station F. Motors 41. and 51 are started'automatically by means not shown and motive'power thus is applied to transmitter 45 and receiving printer 44. Also release of armature'53 has released the cam drum of printer 54,

which shifts axially and. starts into rotation.

Immediately'thereafter its repeaterselector lever changes .the contactive relations of its contact members 55, opening repeating contacts 52 and closing repeating contacts 56. Normally line 43 icarries current as a marking signal which causes'the printer at terminal station E to hold its armature in non-operating position, but sinc the circuit of line 43 has been opened at contact 52,'the line current ceases, thus releasing the armature of the printer and starting the motor .atterminal station E. Upon restoration of interrupting key 46, the normal marking current is restored to line 42, magnet 48 becomes energized and attracts its armature at the repeating 'station F, which'causes the selector lever to return to' itsnormalposition, restoring the repeating contact members 55 to their normal positions asLshown, thus restoring the normal condition of current in line 43, whichreturns terminal station E'to its normal condition. All motors having been started by this operation of interrupting key.46,-ithe operator-at terminal station D may send a: message. Every movement of transmitter- 45,..controls magnet 48Jto repeat the movement, and magnet 48 in turn controls its cam drum and repeater selector lever. to operate the repeating contact members 55 which, when thus controlled, repeatv into line 43 every signal generated in line, 42 by transmitter 45,'thereby' repeating at minal station D. Meanwhile, opening of repeating3contact52 has opened the circuit of magnet 49 -which had extended from battery through magnet 49 and contact 52 to line 43 andto ground atterminal station E. In th operation of contact members 55, contact 56 is closed before contact 52 is opened, thus providing in advance a substitute circuit for magnet 49, extending from battery through magnet 49 and contact 56 to ground 50. This substitute circuit constitutes a reflection estoppel circuit and magnet 49; therefore does not-repeat any transmission signals into the line 42. Interruption of transmission may be-effected by opening the inter-- ruptingr-key at terminal station E for a short period of time, thus opening the line 43 whereupon either forthwith, or at the end of the instant signal, if spacing, the open line 43 will deenergize the line magnet 49, which will operate itsrassociated repeater to open the line 42, after which the printer 44 at terminal station D will be unresponsive to the transmitter 45 since no current, can flow in'line 42, by which non-response of the printer, the operator at terminal station D will note that terminal station E is interrupting-and desires to transmit.

a According to'the foregoing description of th apparatusembodied in Fig. 2, reflection estoppel is achieved from either line-42 or 43 by energizing, under'local control, the electromagnet of the companionrepeating mechanism and thus preventing its operation and. the transmission of signal impulsesto the;line conductor under its, control. Specifically, let it be assumed that transmission is from line 42 to line 43. Electromagnet 48 of repeater 54 is included in such circuit andrespondsto the impulses impressedon line 42 due to the operationof the. transmitter 45 and efiects the, corresponding control of cam drum 54A, and the operation of selector lever 54B which closescontacts 56 and opens contacts 52. *HOWever,'contacts 56close'before contacts 52 open resulting in continuing the circuit for electromagnet 49 which now extends from grounded battery; winding of electromagnet .49,

contactspring 55, contacts-56, and resistance 58 to ground 50; Under such conditions, electromagnet 49' is maintained energized, the camdrum controlled thereby remains stopped, and contacts 5| are not opened so that printer 44 willnotrespond to the operation of contacts 52,

and reflection of signal impulses on line 42 is thus prevented. s

-During all interchange of transmission be tween the ;tWo' terminal stations D and E, all transmission originated at station D will operate magnet 48 of printer 54 and will be recorded upon printer 54, while,'all transmission originated atterminal'station'E will operate magnet 49 and will-be recorded'upon the printer of magnet 49. Thus at the repeating station F the direction of transmission, whether from terminal station D or gterminalstation E, will be indicated and identified by the identity'of the printer at station F upon which the transmission Will have .beenrecorded.

1 Referring now to Fig. 3, there is disclosed an embodiment of the invention similar in some respects. to'the system disclosed in Fig. 2, except that'th'ere is'but one regenerative repeater mechanism at the repeating station which serves both sections of a single line repeater system. Each of the terminal stations G and H has an individual line H and 62 respectively, also at each of the also bygitsback contactsestablishes;the described terminal stations ,there is a,tranmitter..53;:a receiving printer 64, an interrupting key -65; and a motor 66 with signal-control -means;,n0tshown; which may be; of any 'desiredtype. Each vor the? lines BI and 62 to their respective terminal sta-i tions in'cludes'at the; repeating'station Kaline may 67 and 68 respectively. Line relay. filis' normally'energiz'ed by a circuit extendingpfrom grounded battery 58; resistor69', contact 10 of deenergized relay ll, winding of'line relay 61, line til, interrupting key fiE m'agnet of receiving printer 64, and closed contacts of transmitter 63 to ground. A similar circuit may be :traced through battery 58, resistor 69', contact 12 of deenergized relay 13 ove'rline 62 to ground at terminal station At the repeating station'K there is provided a singleregenerative"repeater mechanism 15 identical with the mechanisrn tik Fig. 2, comprising printing and'repeating m'ech anisms and comprising also an additionalfele= merit, a' arn lfi fixed to the cam drum; 22,Fi'g. 1', which controlsa contactiv arrangement-of three" contact members too'pen one and closethe' other of two local switching contacts 11 and '58. 'These contacts control the application or battery to H and removal of battery fromcertain switching and controlling circuits to be described within the repeating station; Whilecani'lli' is in' norI- mal position, as shown in the drawings, the contact TI is closed and the contact 18 is opened, but at all'times when cam H5 is out ofits normal position, the reverse is true and contact [8 is closed while contact 11 is opened. assume BI and G2ihas also 'a local relay o'r seizing relay]? and H, respectively, each of which is operated in a manner to be described for the purpose o f seiz-j ing the regenerative repeater mechanism ar-er the exclusive use of its associated line'fiiforfiz.

The energizing circuit for relay 13,1forrried1byj relay; 61 in. response to .a signal of open ci1'"c' 1 iit nature originated at'break key may bet'ra'cedi from grounded battery 59 through contact "11, lower winding of relay 13, back contact' 'and armature of 'deenergized line relay 61', and front contact and armature of energized line' lre la'y '58 to ground, the relay 13 being provided also with; a

locking winding whose circuit may be traced from grounded battery 59 through contact 18,

upper winding of relay [3, and through contact. and upper armature of relay 13 when energized,

to ground, Similar circ'uits may be'traced fo r. energizing and locking windings of seizing'relay 7 I. Ihe operating magnet 19 in regenerative re-l peating mechanism 15 is included in'a local repeatingcircuit extending from grounded battery 59 through the winding. .of magnet 19, wire 88, front contact and armatureof line'relay 57,- and front contact and armature of line relay 68 to ground. The operating magnet 19, therefore, may be controlled by th front contact of either of the two line relays 5] and 88, while the-back contacts of ;the two lineirelays control the energizing windings of their local seizing :relays l3 and ll respectively. Each seizing relay also shunts the front contacts of its opposing line relay and connects its opposing line section to the,

repeating contacts 8! of the regenerative repeater mechanism, as will appear in the descrip-- tion of operation now. to be given.

Assume that terminal station G desires to deenergizes repeater operating magnet 19.whichresults in starting rotation "of cam '16. Relay 61 sires to transmit;

energizing" circuit for: seizing -relay.;;! 3 whichg;will; energize and operate its c'ontacts interrupting, the normal'circuit of the opposing'line 62-1 and" r n w i cu t f r at l e wh c ma be traced from-groundl at terminal, stationI-I over; line 62,- winding of; line relay 68; contacts -13 or seizing relay'l3 now energized, repeating; contact 8|, resistor '60 andbatteryfifl to ground,;,'I -heg re e e tiv e eat me han sm W c nt nu s: in rotation and operates its cam contacts 1 1 and; 18, immediately t'hereafter opening, its repeating-i contacts 'fl l-, "thus-openingthe circuit tracedyjust, above for'g i e 62 andus ep ati -i to l n tfili and to terminal station I-Lthe, starting signal generated in line 6 l-;by break key fiii; at; terminal Station G. Openingthe :cam. contact J'I ha-s opened; the ener izing circuit of seizing relay 1 3 but before opening the energizing circuitga hgldingg cuitwwas closed -;thr,ough contact 18, and clos uppe onta vo lay 1 ,A su se u nt mar nc: si al? s een iedyb lo inte c ci in n' key 65 which reenergizes: line relay 51- :whiche n turn .reenergizes operating magnet 19,of ;regen-;.;

erative' repeater mechanism ]5,-resulti ng in closg e r n c ta t ire a i erinto start-stop code of signalsgwilloperateas doesgthe opening of the interrupting key described-above afterwhich, throughout the separate andseveral signals'of the ensuing. code combinationof sig} nals; generated by transmitterv 63,-. linev relay in ;will,repeat theseparate-signals to m agnet lg, ofv

regenerative repeater mechanism ,l5,-.whicht hen 3 wilLrepeatthe separate signals by;ac tion of re-t peating contacts 8l=into the line 52, and tog-the terminal station At ,thefend of a start-stop"- code group of1 signals, transmitter" 63 will close; its contact-to generate the stop signal ofthe code group, cam 16 will complete itsgcycle o f;,revolu-a tion, and the entire. system will b e restored toi its-condition ofgrest; Transmitter 6-3 immediately may seize the system fortransmission,;;otanother code combination; of signals, or 1 at this 1 time terminal station H may interrupt the trans mission. UH Interruption oftransmission may be efiected .b yopening the interrupting key-at; terminal sta tionv H for ashort period of time, thus opening, thev line 62, whereupon,but-not until theendof: the instant code combination ;of signals, or, not. until the cam 16, has restored its contacts-111 andl8 to normal, the-open line 62; wil1 deenergize,

the line magnet 68 which willoperate'itsassoi'wi ciated seizing relayigll and will seize; the regen-Q erativerepeater mechanism fii to .-;open the line 61, after which the printer 64 at-terminal sta-f tion G will be unresponsive to'its transmitter63 3. sinc no current can flow-in line nfilgbyiwhicn non-response of the receiving printer 64, the. op'-; erator. atterminal-station G maybe advised that: the terminal station H is interruptingand .de i- Reflection estoppel in the case of the'structure of Fig. 3, is achieved: by arranging control: relays under the control of contacts operated by i. acam of the repeater unit. =Such control is ef-' fected by contacts 1-! and TSfrom-cam 16 which; as described,forms-apart of the repeater unit l5 actuated upon the original seizureof the line? circuit. -For exampley-if station' G- is transmit ting-through repeater 15 to station H; relay61 is deenergizedtoclose its back contact and-'i'nv isyreleased for rotation. Upon the initial rotationof'cam I6, contactI'Iis opened andcontact I8 isclos'ed, whereupon theoriginal energizing circuit of relay I3 is opened and a-lockingscir-= cuitfor such' relay is established extending from grounded battery, contact 18, upper'winding' and front contact of relay I3 to-groundq Relay I8 is thus maintained energized for each cycle of operation of cam -18'and the repeater I5, and

appliesa shunt to the contacts of relay 68' so that even though such relayma y follow the siggn'als,-it can exercise no control of the repeater,

and consequently signalswill not beimpressed back on line BI. In thisway, reflection-ensigpnals is prevented. I

"A modification of the system of Fig. 3 is disclosed in Fig. 91 inwhich; terminal station G is;

identical with the terminal station 'G of Fig.- 3,

in which a terminal-stationL-constitutes'a sta-' tion equipped with'apparatus' arranged-according to duplex circuit principles, andin which a' repeating stationNis equipped with a circuit system well known by-the term half duplex in a which isembodied a start-stopregenerative repeater mechanism; 85-Qarranged in some ways similar to the circuits: (bf-Fig.8. As disclosed also inIFig. 3, terminal station G has an individual line 88 extending to the repeating station N and terminating there in the win in of a line relay 81which'also has anassociated seizing relay 88 which,'as in Fig.8, has an energizing; winding whose circuit extends from battery through contact 98 controlledby cam 9|, "lower winding of seizing relay 88, -back contact and armature'ot line relay 81 and ground, and-'alocking winding whose circuit extends from battery through cone tact=92controlled by cam 9|, upper winding of seizing relay 88, front contact and upper armature of relay 88 when energized, and to ground.

' Terminal station L is equipl fid with a receiving printer 93 controlled by contacts of a' polarized line flti and through an interruptingkey 91 to a transmitter 98." Thereis provided'also a motor 99" for sup plying a motive power to the trans-i mitter 98 and receiving printer 93. Transmitter line relay '94 connected to line 95 and to artificial 98n0rmally connects line 95 to positiveor mam ing battery but may connect the line tdnegative or spacing battery for the purposes of propagating" telegraphic-code signals. over. line 95, while interrupting key 9Tnorm'ally connects line 95 to transmitter 98 and. to positive battery, but

whenin its operatedposition connects the line 95 to negative or spacing battery instead for the purpose of producing an interrupting signal in line95. a g 'Ihe terminal station L is'connected by itsin ,dividual line 95 to the repeating station'N where itterminates in the winding'of a polar line relay I 8I which is connected also to an artificial line I82=and to an'armature of a seizingrelay 88, for-a purpose tobe described. There is associated with the'polar line relay lillaseizing-relay I83 which also hasana'energizing'winding whose circuit extends from (battery through contact 98, lower winding of'relay I83; normally'open back contact and armature-of line relay I 8|", front contact'and armature of line relay 81, and to ground, and a locking winding whose circuit extends'from bat-' tery through contact 92 and upper winding of re: lay I83 and top contact and armature of relayj I83, when energized; and to'ground, the relay I 83 having also a grounded armature and front con-1 tact for shunting the grounded'armature and front contact of relay-81 thusrendering contactsof line relay 8! inefiective' during the times that is operating and relay I83 is en-" line'relay I8I ergized' 1 I,

'The regenerative repeater mechanism, has opi-a 'eratingQmagnetIM connected in anoperating circuit extending from battery through winding .ofimagnet I84, front ornormally closed contact;- and' armature of polar line relay I8I,.and front: contact andarmature of line relay 8! to ground, 1

and has also repeating contacts" I85 and I86 which are convertible to be used either under; principles of single-current transmission I when: I

relay 88is deenergized or under principles of twocurrent, transmission when relay 88 isenergized, the repeating contacts I88 being open: at the ar-. mature ofjrelay 88 when the relay 88 is'in ;deener-,v gized condition. seizing relay I83 when ener. gized completes a circuit for single-current transmission from battery through repeating contacts I85, bottom armatureand contact of operated seizing relay I83, winding offneutral line relay 81, line 86, and terminal station G toground,

while seizing relay 88 when energized cor'npletes, circuits for two-current transmission from positive or marking battery through repeating contacts I85 or-a1ternatively from, negative or spacing battery through front contact and middle armature of energized seizing relay 88 and repeating contacts I86, and thence extending for either current over front contact and bottom armature of energized seizing relay 88 to the apexv of polar relay I8I, line 95, to terminal station L, polar receiving relay 94, artificial line 96 and to ground, the relay 88 thusoperating not only as a "seizing relay to seize the regenerative repeater mechanism 85 but also as aconverter'toconvert the regenerative repeater mechanism from single-current transmission principles to twocurrent transmission principles.

7 Terminal station G desiring to transmit a message to terminal station L opens momentarily theinterrupting key at terminalstation G, thus openingthe circuit of line 86 and starting the motor at terminal station G, also deenergizing line relay 8'I, which'by opening its front contact deenergizes the operating magnet I 84 of regenerative repeater mechanism 85 and starts the motor I81 and by closing its backcontact closes thefdescribed energizingcircuit of seizing'relay 88, thus operating the relay 88 and connecting positive or marking battery through contact I85 to the apex of polar line relay I8I and connecting negative or spacing battery to repeating contacts I I88, whereupon regenerative repeater mechanism 85 startsits cam 9I to close the locking circuit of seizing relay'88 and then to open the energizing circuit'the'r'eof and immediately the repeating contacts I85 andI86fare operated to repeat the spacing signal generated by the interrupting key at terminal station G into line 95. The switching of the line from marking battery on contact-s I85 to spacing battery on contacts I86 reverses the polarity of current in line 95 and through polar receiving relay 94 to ground through artificial'line 96, resulting in starting u the motor 99 and in opening the contact of polar 1 receiving relay 94 and deenergizing the magnet 93 of the receiving printer at terminal station L, thus repeating at terminal station L the interruption signal generated by the interrupting key at terminal station G. Upon reclosing the interruptingkey at terminal station G, line relay 81 becomes reenergized, magnet I84 of regenerative repeater mechanism 85 becomes reenergized, restoring marking current to line 95 and reversing polar receiving relay 84 which reenergizes magnet 93 of the receiving printer at terminal station L. Cam 9| stops at normal position shown and releases the locking circuit of seizing relay 88, thus completing the restoration to normal of all parts of the system. The motors having been started, the operator at terminal station G may transmit a message to terminal station L. In each start-stop code combination of signal impulses, the starting impulse of spacing nature deenergizes line relay 81 and regenerative repeater magnet I84, and energizes and locks seizing relay 88, after which line relay 81 is controlled by contacts of the transmitter at terminal station G under principles of single-current transmission, regenerative repeater magnet I84 is controlled by contacts of relay 81 under principles of single-current transmission, and polar receiving line relay 94 is controlled by regenerative repeater contacts I85 and I86 under principles of two-current transmission, while at the end of each code combination of impulses all parts of the repeating system are restored to their conditions of idleness.

Should the operator at terminal station L desire to interrupt the transmission, interrupting key 81 may be operated for a short period of time, thus impressing negative or spacing current upon line 95 and instantly the polar line relay 'I8I will respond and reverse the position of its armature, after which at the end of the instant code cycle and when cam 9| reaches its normal position and restores its contacts 98, the described energizing circuit of the seizing relay I83 will be completed, thus opening the circuit of line 88 which now will extend through winding of neutral line relay 81 and over front contact and bottom armature of seizing relay I83, through contact I88 to open contact of relay 88, itbeing borne in mind that the spacing condition of polar line relay I8l maintains its upper contact open and therefore maintains regenerative repeater magnet I84 deenergized and maintains regenerative repeater contacts I85 open and I86 closed, after which the receiving printer at terminal station G will beunresponsive to its transmitter since no current can flow in line .86, by which non-responsive condition the operator at terminal station G may be advised that terminal station L is interrupting and desires to transmit.

Terminal stationL desiring to transmit a message to terminal station G may operate interrupting key 91 which in its operated position switches line L from positive or marking battery to negative or spacing-battery thus reversing the polarity of current in line'85 and starting the motor 99, also reversing the polarity of polar line relay I8! which by reversing the-position of its armature and by opening its upper contact, deenergizes the operating magnet I84 of the regenerative repeater mechanism 85 and starts motor I81 and by closing its lower contact, closes the described energizing circuit of seizing relay I83, thus operating relay I83, after which the regenerative repeater mechanism 85 starts its cam ill to close the locking circuit of seizing relay I83 and then to open the energizing circuitthereof,

and immediately the repeating contacts I are opened to repeat the spacing signal generated by interrupting key 91 at terminal station L into line 86. Opening line 86 deenergizes the magnet of the receiving printer and starts the motor at the terminal station G, thus repeating at terminal station G the interruption signal generated by the interrupting key 91 at terminal station'L. Upon restoring the interrupting key to normal at terminal station L, the polarity of current in line becomes reversed, polar line relay I8I restores its armature, and magnet I84 of regenerative repeater mechanism 85 becomes reenergized, restoring marking current to line 86 and reenergizing the magnet of the receiving printer at terminal station G. Cam 9I stops at normal position shown and releases the locking circuit of seizing relay I83, thus completing the restoration to normal of all parts of the system. The motors having been started, the operator at terminal station L may transmit a message to terminal station G.

In each start-stop code combination of signal impulses the starting impulse of spacing nature reverses the polarity of polar line relay IN and deenergizes regenerative repeater magnet I84 and energizes and locks seizing relay I83, after which polar line relay I8] is controlled by contacts of transmitter 98 at terminal station L under principles of two-current transmission, regenerative repeater magnet I84 is controlled by contacts of line relay l8! under principles of single-current transmission, and the receiving printer at terminal station'G is controlled by regenerative repeater contacts I85 under principles of singlecurrent transmission, while at the end of each code combination of signal impulses all parts of the repeating system are restored to their conditions of idleness. Should the operator at terminal station G desire to interrupt the transmission, the interrupting key at terminal station G may be operated for a short period of time, thus opening the circuit of line 85 whereupon but not until the end of the instant code combination of signals or not until the cam 8| has restored its contacts 98 and 92 to normal, the open line 88 will deenergize the line relay 81 which then will energize and operate its associated seizing relay88 and Will seize the regenerative repeater mechanism 85 to reverse the polarity of the current in line 85, whereupon polar receiving relay 94 instantly responds and opens its contact, thus deenergizing the magnet 83 of the receiving printer at terminal station L within which printer the cam drum 22, Fig. 1 will spin, which will constitute a signal to the operator at terminal station L that the operator at terminal station G is interrupting and desires to transmit.

Reflection estoppel is eiiected in a manner identical with that described'for Fig. 3; namely, through the control of relays I83 and 88, from cam 9|, and contacts-98 and 92. Since the operation issimilar'to that for Fig. 3, repetition is not deemed necessary.

vAs disclosed in Fig. 5, the system of this invention may comprise two mechanically operated electrical switches for changing the connections of the regenerative repeater mechanism to render it responsive to one or the other .of two line. sectionsbetween which it functions. In Fig. 5,.terminal-stations G2 and 1-12 are identical in equipment and function with the terminal stations G and H of Fig. 3, each terminal station being connectedto a repeating station P bya line H8 and III respectively, which terminate at the repeating station P in windings of two line relays H2 and H3 respectively, both line relays being normallyiin energized condition by current for line IIO over a line circuit extending from grounded battery through winding of a detector magnet II4, closed contacts of unoperated switch H5, winding of line relay II2, line H0, and terminal station G2 to ground, while for line II I a similar circuit but not including the detector magnet I I4 may be traced from grounded battery through resistor I I6, closed contacts of unoperated switch I I I, winding of line relay I I3, line I I I, and terminal station H2 to ground. It will be seen that both line relays H2 and I I3 as well as the detector magnet I I4 are held normally energized while the system is in condition of idleness, that if activity is initiated by opening line H0, both line relay H2 and detector magnet II4 will become deenergized simultaneously, but that if activity is initiated by opening line I I I, the detector magnet I14 will not be deenergized immediately. The utility of this selective feature will appear in the description of operation of this embodiment of the invention.

A'regenerative' repeater mechanism IIB similar to mechanism 54, Fig. 2, is provided, its operating magnet H9 being included in a repeating circuit extending from grounded battery through winding of magnet I I 9, contacts of line relay I I3, and contacts of line relay II2 to ground so that it-may be controlled by either one of the two line relays H2 and I I3 which in turn are controlled by the two terminal stations G2 and H2 respectively. Repeating contact I20 is connected in a normally open circuit extending from grounded battery through resistor I2I to the open left-hand contact member of switch II also to the open left-hand contact member of switch II! from either of which two members the repeating circuit may be completed either by operation of switch II5 to complete the repeating circuit through winding of line relay II2, line H0, and terminal station G2 to ground or by operation of switch II1 to complete the repeating circuit through winding of line relay II3, line III, and terminal station H2 to ground. Operation of switches H5 and II! is efiected by striker rods I2I and I22 respectively, which are operable alternatively by an operating member I23, which is positioned by the armature I 24 of detector magnet I I4 and is operated by camfollower lever I25 pivoted upon fixed pivot I26 and moved by cam follower I21 working in cooperation with cam I28 which is attached to cam drum 22, Fig. 1, of the regenerative repeater mechanism II8.

Armature I24 when attracted, holds cam follower lever I23 in position to operate rod I2 I and when retracted, holds the cam follower lever in position to operate rod I 22. Spring tension of contact members of switches H5 and I" returns the rods to normalcy when not controlled by cam I28 and cam follower lever I25.

Operation of the structure disclosed in Fig. 5 is as follows, all magnets and relays shown being normally in energized condition by reason of currents in the several circuits described above. Assume that terminal station G2 desires to transmit a message to terminal station H2, the interrupting key at terminal station G2 may be operated momentarily, resulting in starting the motor at terminal station G2 and in deenergization of detector magnet H4 and of line relay II2, whose contacts deenergize regenerative repeater operating magnet H9 and start the motor of the regenerative repeater mechanism II 8. Deenergization of magnet I I4 has released its armature I24 whichjhas moved the member I23 into position for operating rod I22 instead of rod I2 I and the deenergization of the magnet H9 together with the starting of the motor of the regenerative repeater mechanism has started the cam I28, which controls cam follower I21, to rotate the follower arm I25 and.- operating member I23 which operates rod I22 and reverses the contactive relations of the contact members of switch H1, removing line III from its battery through resistor I I8 and extending line I I I instead through the left-hand contact member of operated switch I! to the repeating contact I20 and throughresistor I2I to battery. Immediately the regenerative repeater mechanism II8 opens contact I20, thus opening line II I and repeating into line III and to terminal station H2 the interruption signal of spacing nature generated by terminal station G2. Upon reclosing the interrupting key at terminal station G2, the circuit of line H0 is closed, relay 2 and magnet H4 are reenergized, without moving armature I21, since operating member is positioned under the projecting end of rod I2 I and is not allowed to rise, repeating magnet H9 is reenergized, and repeating contact I20 is reclosed, thus reclosing line II I and repeating into line I I I and to terminal station H2 the marking signal generated at station G2, after which cam I28 will complete its cycle of rotation and.

will stop, permitting follower I 21 and. follower lever I25 to return to normal and to return member I23, switch I", and armature I24 to normal.

The motors having been started, the operator at terminal station G2 may send a message to terminal station'HZ. Throughout the transmission of the message, a starting impulse of spacing nature in a start-stop code of signals will operate as has been described above for the spacing signal generated by the interrupting key, after which the separate and several signals of the ensuing code combinations of signals generated by the transmitter at terminal station G2 will control line relay II2, contacts of line relay II2 will 7 repeat the separate signals into magnet II9 of regenerative repeater mechanism I I8 which then will repeat the separate signals by action of repeating contacts I20 through the line relay H3 into the line I II and to the terminal station H2, reflection signals being prevented by the righthand contact members of operated switch II! which shunt the contacts of the line relay II3. At the end of the start-stop code group of signals the transmitter at terminal station G2 will close its contact to generate a stop signal of marking nature, cam I28 will complete its cycle, and the entire system will be restored to its condition of rest. Interruption of transmission may be effected by opening the interrupting key at terminal station H2 for a short period of time, thus opening the circuit of line II I whereupon, but not until the end of the instant code combination of signals or not until cam I28 has restored switch II! to normal, the open line III will deenergize line relay II3 which will seize the regenerative repeater mechanism in a manner to be described herein immediately below, after which the receiving printer at the terminal station G2 will be unresponsive to its transmitter since no current can flow in line H0, by which non-response the operator at terminal station G2 may be advised that theoperator at terminal station H2' is interrupting-and desires to transmit.

Assume that terminal station H2 desires to transmit a message to terminal station G2. the

interrupting key at terminal station H2 may be opened momentarily, resulting in starting the motor at terminal station H2 and in deenergization of line relay H3 whose contacts deenergize regenerative repeater operating magnet H9 and start the motor of the regenerative repeater mechanism H8. Continued energization of detector magnet I I4 maintains member I23 in position to operate rod I2I, and the deenergization of magnet H9 together with the starting of the motor of the regenerative repeater mechanism has started the cam I28 which controls cam follower I21 to rotate the follower arm I25 and operating member I23 which operates rod I2 I and reverses the contactive relations of the Contact members or switch H5, removing line H from its battery through magnet H4 and extending line HI] instead through the left-hand contact members of operated switch H5 to the repeating contact I and through resistor I2I to battery. Immediately the regenerative repeater mechanism H8 opens contact I20, thus opening line H0 and repeating through relay H2 into line H8 and to terminal station G2 the interruption signal of spacing nature generated by the interrupting key at terminal station H2, reflection signals being prevented by the right-hand contacts of switch H5 which shunts the contacts of relay I I2. Upon reclosing the interrupting key at terminal station 1-12, the circuit of line III is closed, relay H3 is reenergized, repeating magnet H9 is reenergized, and repeating contact I20 is reclosed, thus reclosing the circuit of line HI] and repeating into line H0 and to terminal station G2 the marking signal generated at the terminal station H2, after which cam I28 will complete its cycle of rotation and will stop, permitting follower I21 and follower lever I25 to return to normal and to return member I23, rod I2I, and

switch I I5 to normalcy. The motors having been. 4

started, the operator at terminal station H2 may send a message to terminal station G2. Throughout the transmission of the message a starting impulse of spacing nature in a start-stop code of signals will operate as has been described above for the spacing signal generated by the interrupting key, after which the separate and several signals of the ensuing code combination of signals generated by the transmitter at terminal station H2 will control line relay H3, contacts of the line relay will repeat the separate signals into magnet I I9 of regenerative repeater mechanism H8, which by its contact I20 will repeat the separate signals through the line relay H2 into line H0 and to the terminal station G2. At the end of the start-stop code group of signals the transmitter at terminal station H2 will close its contact to generate a stop signal of marking nature, cam I28 will complete its cycle, and the entire system will be restored to its condition of rest. Interruption by terminal station G2 of transmission from terminal station H2 may be effected in a manner similar to that described above for interruption by terminal station H2, the circuits involved in the interruption being already fully described above.

A direction-indicating mechanism in the printing equipment controlled by the regenerative repeating mechanism I I8 and more specifically controlled by its cams 25, Fig. 1, for modifying the record to indicate the direction of transmission is illustrated in the form of a ribbon shifting device for using one or the other color of a twocolor ribbon. Type I4I strikes ribbon I42 on its upper color band I43 when a pivoted arm I44 rests against its stop I45, thus holding ribbon I42 in its lower position. Shifting of pivoted arm I44 into contact with its stop I46 permits ribbon guide I41 to rotate upon fixed pivot I 48 under tension of spring I49 to lift ribbon I42 into its upper position, thus bringing the secondcolor band I5I of the ribbon into alignment with the type I4I so that the color of the record is changed in accordance with the position of the rocking arm I44. The change in position of pivoted arm I 44 is attained by rocking a lever I52 on fixed pivot I53 when engaged by operating member I23 at lower or upper anvil I54 or I55, resulting in shifting the rocking lever I52 and pivoted arm I44 and their connecting link I55, the shifted elements being held in one or the other of their positions by jockey I51. It will be seenthat the operating member I23 in its elevated position as shown moves to operate rod I2I and also will engage anvil I54 and will operate lever I52, link I55, and arm I44 into their upper positions to cause the type IM to print through the lower color band I5I, while when in its depressed position it moves to operate rod I22 and also will engage anvil I55 and will operate lever I52, link I56, and arm I44 into their lower positions to cause the type I4I to print through the upper color band I43. During the transmission described from terminal station G2 to terminal station H2, the type MI and others, not shown, have operated to print utilizing the color band I43 of the ribbon I42 since operation of cam lever I23 with magnet H4 deenergized and with armature I24 retracted results in operation of switch H1 and engagement of cam lever I23 with anvil I55,

thereby rocking the lever I52 into position shown, shifting link I56 downward and rocking lever I44 into engagement with its lower stop I45, thereby lowering ribbon I42 into position shown where type I4I strikes the upper color band I43. During transmission from terminal station H2 to terminal station G2, the type I4I has operated to print utilizing the color ban-d I5I of the ribbon I42 since operation of member I23 with magnet H4 energized and with armature I24 attracted results in operation of switch I I5 and engagement of member I23 with anvil I 54, thereby rocking the lever I52, shifting the link I55 upward and rocking the lever I44 into engagement with I the upper stop I45 which permits spring I49 to rotate ribbon guide I41 upon its fixed pivot I48, thereby lifting ribbon I42 into position where type I4I strikes the lower color band I5I. Magnet H4 becomes deenergized by operation of switch II1 under control of terminal station H2 or by all spacing signals under control of terminal station G2, but at the end of each revolution of cam I28 the operated switch H5 or H1 is restored by cam I28 and magnet I I4 is reenergized in preparation for a subsequent code cycle.

Reflection estoppel for the system of Fig. 5 is attained by providing electromagnet H4, which, through its armature I24, controls member I23 and the operation of rods I2I and I22. If transmission is from line I Ill to line I I I, relays I I2 and electromagnet H4 will be energized and member I23 will be in the position shown in Fig, 5. Consequently, for each operation of cam I28, which is a part of the repeater, rod I2I will be operated and contacts H5 will be operated for applying current to the contact of relay H2, and thus effectively shunting its contacts so that even though its armature follows the signals it will exercise no control and signals will not be repeated back to the originating station.

In Fig; 6 are illustrated two "regenerative re-- peater mechanisms I61 and I 68 serving two I sec-e tions of a single telegraph line and having a ventional printing telegraph transmitting and receiving device.

Each repeater comprises identically the same parts bearing the same reference numerals ex-- cept in the case ofv the repeater for line section 2I 6 j, the ;reference numerals are distinguished from those applied tothe parts of the repeater forflinegsection 2 I8 by a prime mark and includes aqstartestopcam sleeve I1I carrying four cams; a sta'rtingfcam I12, a latch restoring cam. I13, an interlocking Canal", and a. signal cam I with cam lobes I11. ;A, stop latch I8I upon a fixed pivot I82 engages cam I12 and restrains cam sleeve I1I against rotation by power communicated through a friction clutch. A start latch I83 is pivoted onpivot I82 and is restrained by its engagement with armature I84 whilethe armature is in its normal or marking position by energized magnet I85. Start latch I83 has striker I86 which may engage and operate stop latch I8I to disengage and release cam I12. Start latch I83 also has cam follower I81 operated by cam I13 to restore latch I83 after its release by armature I84. t

Operation of these two latches under control of armature I84 is as follows: Upon deenergization of magnet I85 its armature I84 is released and is drawn by spring I9I into spacing position, thereby releasing start latch I83 which rotates under tension of spring I92 and causes lug I86 to engage and rotate latch I8I against the tension of spring I93, thus lifting latch I8I from cam I12 and releasing cam sleeve "I, which then rotates and immediately causes cam I13 to engage and to operate follower I81 which rotates start latch I83 and lifts it and holds it clear of armature I84 throughout the then ensuing code period and until after the stop-signal impulse has been received.

Each cam sleeve I1I also has an interlocking cam I14 whose followerl95 operates a rocking lever I96, pivoted on one fixed pivot I91. Lever I96 is tensioned by aspring I99. At the other end of each lever I96, I96 is an interference lug I98 which, while in its operated position obstructs the armature I84 of an associated repeaterand mechanically holds that armature in marking position.

Each cam sleeve "I has also a signalling cam I15 having multiple lobes I11, one lobe for each individual signal impulse in a code cycle, seven being shown in the illustration of Fig. 6. The further structure of Fig. 6 will be more fully understood with reference to Patent 1,370,6691issued March 8, 1921, to L. M. Potts for Machine telegraph. I

A signal lever I ispivoted loosely on-a fixed pivot 202,'is tensioned by spring 203 and is further supported by guides not shown. A contact lever 204 pivoted upon the fixed pivot 205 operates contacts 296 and is restrained by jockey 291. Signal lever 20I has two mechanical lugs 2H and 2I2 adapted to strike lever 294 to move it clockwise or counterclockwise selectively. Signallever 20I has also a cam follower 2I3 cooperating with cam, lobes I11 on cam I15 and has a pivot lug 2I4 adapted to be engaged and restrained by armatur I84 in such manner that.

wh'en armature. I84, is, in. marking condition. the

lug 2I4 is free to move andsignal lever 2,0I ,is free to rotate'upon its fixed pivot, 292. When armature I84 is in spacing condition, the, armature I84 engages the lug 2I4 and locks the,lug endzof the. signal ,lever 20I ,so that thevsignal lever is not free to rotate uponits pivot 202 when actuated by a lobe I11 of, cam I15, but must 111-, stead be lifted from its pivot, against the tension of. spring 203 and must rotate upon pivot .lug2l4 engagingarmature I84 as a pivot.

Operation of signal lever 20I and of lever 204 is .as follows), 'Whenactuated by cam I15 witharmature I84 inumarking, position, lever 20I rotates upon pivot 202 andoperates 1ug 2l2 to engage lever .204 to rotate lever 204 clockwise to close electrical contact 206 into marking condition as shown, themarking condition of contacts being then, continued by jockey 291 or on the otherhand, when actuated by. cam I15 when armature I84 is inspacing condition, the signal;

lever 20I rotates upon pivot lug 2I4 with armature I84 as a pivot and operates lug 2 to en gage and rotate lever 204 counterclockwiseto open electrical contacts 206 into spacingcondition, which condition is. then maintained by jockey 201.,

The two repeater mechanisms, I61 and I68 are,

related mechanically through interlocking levers I96 and I96 and are further related electrically through circuits of two line sections. The line section conductor 2I6 is connected to upper contact 296 and an extension conductor 2I1 connects lower contact 206' to winding of magnet I85 connected to a source of current. The second line section conductor 2I8 isconnected to upper contact 206 and an extension conductor 2I9 connects lower contact 206 to winding of magnet I85 connected to a source of current.

Operation of the entire system of Fig. 6 is as follows. A startingsignal of'spacing nature in first line section 2I6 deenerg-izes magnet I85, whereupon spring I 9| draws armature I 84 from under starting latch" I83, which then is rotated on its pivot I82 by'its springl92 to cause its lug I86 to engage and to rotate latch I8I against tension of its spring I93 to lift latch I8I out of cam I12, thereby freeing sleeve I1I which rotates with its four cams, I12, I13, I14, and I15. Cam I 13 by its follower I81 lifts latch I83 to clear armature I84, and cam' I14 rotates lever I96 upon its p-ivot I91 to lift its lug I98 to "engage armature I 84, resulting in locking the armature I84 mechanicallyin its marking position, thus rendering the armature. I64 unresponsive to tension of its spring I9I duringflthe period lever I 96is operated. Cam I15 now operates one of its lobes I11 against cam follower 2I3 on lever 20I, rotating the lever 29I upon its Contacts 206 become disengaged, by their own spring tension and thus open the circuit of second line section 2I8, thus repeating in line section 2| 8 the starting signal of spacing nature described. gizes magnet I85 but without effect since armature I84, isnot now responsive to. telegraphic.

signals manifested in magnet I85, it being locked contact 5 Opening the contacts 206 deener journaled in brackets 232 and 233 respectively,'

in its marking position by lug I98 in its operated position.

Each of the seven lobes I11 on cam I operates signal lever 28I which in turn may or may not operate lever 284 to change the condition of contacts 286 as required to repeat an instant received signal manifested in magnet I85. Should the instant received signal be of marking nature, armature I84 is attracted, lug 2I4 moves without engaging armature I84, lever 28I rotates on pivot 282, lug 2 I2 engages and rotates lever 204, to close contacts 288 to produce a repeated marking signal in line section 2I8 unless the prior signal in line section 2 I8 has been marking, in which case lever 284 is currently found in marking position and the operation of marking lug 2 I2 is without effect. Should the instant signal in magnet I85 be spacing, armature I85 is retracted, lug 2I4 engages armature I84, lever 28I rotates upon armature I84 as a pivot, and spacing lug 2II engages lever 284 to operate contact 286 into open condition to produce a repeated spacing signal in line section 2I8 unless the prior signal in line section 2I8 has been spacing, in which case lever 284 will be currently in spacing or counterclockwise position and will remain in that position, spacing lug 2 thus operating without effect.

Selective action of lever 28I occurs seven times in each code cycle, first for the starting impulse, then for five character code impulses, then for a stop signal, after which the notch of cam I12 passes under latch I8I which by tension of its spring I93 engages the notch and stops the cam sleeve I1I with the notch of cam I13 positioned under cam follower I81 of latch I83 which latch thus is permitted to engage armature I84 in condition to receive a subsequent starting signal and with the notch of cam I14 under cam follower I95 of interlocking lever I96 so that spring I99 rotates lever I96 upon pivot I91 to withdraw lug I98 from armature I84. This completes a cycle of code transmission by control of line section 2 I6 repeating into line section 2 I 8, and the operation of repeating into line section 2I6 by control of line section 2l8 and line magnet I85 is similar. Each signal impulse interval is timed in its beginning and ending by the several lobes I11 of cam I15 and is controlled as to marking or spacing nature by the operation of the armature of magnet I85 which is responsive at all times to the instant signal in a controlling line section.

Interruption in the transmission is effected by opening the receiving line section for an interval, whereupon during the stop signal condition of the transmitting line section the open circuit condition of the receiving line section will operate to seize the alternative repeating mechanism and to render the home recorder of the instant transmitting station unresponsive to the operating transmitter, thus notifying at the transmitting station that the then receiving station desires to transmit.

In Fig. 7 is shown motor control mechanism for the apparatus of Fig. 6 wherein a single motor drives either of the two associated repeating mechanisms and is controlled to start by a signal in either of the two associated line sections.

Upon a frame plate 23I are fixed brackets 232, 233 in which are journaled respectively shaft 234 carrying cam sleeve I1I driven through friction clutch 236 and shaft 234' carrying cam sleeve I1 I driven through friction clutch 231. Latches I8I and I8I are fixed upon pivot rods I82, I82,

while latches I83, I83 are pivoted loosely upon pivot rods I82, I82. Fixed also upon pivot rods I82 and I82 are cam followers 238 and 239 respectively, which follow screw thread cams 248 and 24I respectively. Cam 248 slides upon shaft 234, being at all times under tension of spring 242 and being rotated with the shaft 234 by spline 236'. Adjacent to cams 248 and MI are snap switches 244 and 245 with operating arms 246 and 241 positioned to be engaged by flanges 248, 249, 258, and 25! fixed to cams 248 and MI. In operation, cam follower 238 which is without longitudinal movement, engages cam 248 by reason of rotation ofpivot shaft I82. Rotation of shaft 234 will rotate cam 248 which, by reason of engagement with cam follower 238, will slide upon shaft 234 toward frame plate 23I until flange 248 engages arm 246 and moves arm 246 to reverse the mechanical condition of snap switch 244 to open its contacts 252.

A motor 254 driven from a source of power 255 when either contact 252 or 253 is closed operates through gears 256 to drive a common shaft 251, which through gears 258 drives shaft 234 and through gears 259 drives shaft 234'.

The operation of the motor control system in Fig. '1 is as follows. Receipt of a starting signal of spacing nature by line magnet I deenergizes the magnet and releases its armature I84 which by spring I9I is drawn from under latch I83, which rotates freely upon pivot shaft I82, and with its lug I86 engages latch I8I, which rotates pivot shaft I82 and its cam follower 238, to lift the cam follower 238 away from the cam 248, thusreleasing cam 248 which is propelled along shaft 234 by compression spring 242 until flange 258 engages operating arm 2,46 and operates snap switch 244 to close its contacts 252 which close an obvious circuit including source 255 and motor 254 so that the motor 254 is started and thereafter drives shafts 251, 234, and 234' continuously. Should the starting signal be received by magnet I85 instead; lamh I83 would have been released to operate latch I8I, pivot shaft I82 and cam follower 239 to release cam 24I which when operated under power of compression spring 243 would propel flange 25I to engage arm 241 to reverse the mechanical condition of snap switch 245 to close contacts 253, instead of 252, which would complete an obvious circuit to start motor 254, after which the motor would drive shafts 251, 234, and 234 continuously. Thereafter at each completion of a rotation of cam I12, latch I8I will engage the notch of cam I12, thereby rotating pivot shaft I82 to permit cam follower 238 to reengage cam 248, a disengagement being effected immediately upon receipt of the immediately succeeding start signal.

After the cessation of signalling, the absence of start signals will permit cam follower 238 to remain continuously in engagement with cam 248 for an interval sufficient for cam 248 to move along shaft 234 until its flange 248 engages arm 246 to reverse the mechanical condition of snap switch 244, thereby opening its contacts 252 to interrupt the circuit and to stop the motor 254.

When breaking, as described in connection with Fig. 6, the original transmission over controlling line section 2I6 will operate motor 254 by control of contacts 252 and the break under control of line section 2I8 will operate latch I8I and cam follower 239 to reverse the mechanical condition of snap switch 245 to close its points 253 so that for an interval motor 254 will have its power circuit ."closed by contacts? 252 and 253 in parallel. Each of the snap switches. 244 and 245 will be reversed to open its contacts vunder controlof its cam 240 or 24! by control of its own linesection H6 or 2 l8 and independently of the continuance or cessation of transmission under control of the associated line section, and the'motor 254 may stop only when transmission has ceased upon both line sections for a suitable period. I

According to the structure of Figs. 6 and 7, estoppel results from the fact that the armature of the repeating mechanism for the incoming line section is blocking mechanically, armature I84 being blocked by latch I96 when cam H4 is in rotated position in response to operation of armature I 84.

Although the invention has been described in connection with a specific form thereof, it will be understood that it has further applications and it is not intended to be limited in scope by the embodiment shown herein for illustration.

The invention claimed is:

1. In a telegraph repeating system, two line sections, a line relay for each line section, an auxiliary relay for each line relay, a rotary repeating mechanism common to said line relays and operable initially by either of said line relays, and electrical contacts controlled by said rotary repeating mechanism after operation of one of said auxiliary relays to disable the other one of said auxiliary relays.

2. In a telegraph repeating system, two line sections, a line relay for each said line section, a rotary repeating mechanism common to said line relays and operable initially by a first actuated one of said line relays, a signal-receiving magnet and retransmitting contacts in said rotary repeating mechanism, and electrical contacts controlled by said rotary repeating mechanism after operation of said first actuated one of said line relays to associate said signal-receiving magnet with said first actuated one of said line relays and with its line section and to associate said retransmitting contacts with the other of said line sections.

3. In a telegraph repeating system, two line sections, a line relay for each said line section, a rotary repeating mechanism common to said line relays and operable by a first actuated one of said line relays, repeating electrical contacts in said rotary repeating mechanism and adapted to repeat received signals, and further electrical contacts controlled by said rotary repeating mechanism to associate said repeating contacts with the instantly unactuated one of said line relays.

4. In a telegraph repeating system, two line sections, a regenerative repeater mechanism having retransmitting contacts associated with said line sections and normally disconnected there from, mechanically operated means for operating said contacts, means for connecting said contacts during their operation to either of said line sections to repeat into either of said line sections under control of received signals received from the other of said line sections, and means controlled by the starting signal impulse of a start- I stop code of signalling conditions to determine the operation of said connecting means and thus the connection of said contacts to one of said two line sections and to effect such connection.

5. In a telegraph repeating system, two line sections, a single printing and regenerative repeating mechanism associated with said two line sections, circuits and switches between said mechanism and said two line sections and adapted to connect said mechanism between said two line sections in alternative manner to repeat.

impulses into either'of said line sections alternatively under control of signalling conditions received from the other of said line sections, a pilot magnet controlled by one of said two line sections, and selectors controlled by said pilot magnet to select a desired switch. 1

6. In a telegraph repeating system, two line.

to adjust printing elements in said mechanism to identify a selected switch.

'7. In a telegraph repeating system, twoline sections, a single printing and regenerative repeating mechanism associated with said two line sections, means adapted to connect said mechanism between said two line sections in alternative manner to repeat impulses into either of said line sections alternatively under control of ,signalling conditions received from the other of said line sections, and means controlled by one of said two line sections to determine the manner of connection. I

8.'In a telegraph repeating system, two line sections, a single printing and regenerative repeating mechanism associated with said two line sections, means adapted to connect said mechanism between said two line sections in alternative manner to repeat impulses into either of said line sections alternatively under control of signalling conditions received from the otherof said 

